hibernate的多对多配置

 1 package com.xiaostudy.domain; 2 ?3 import java.util.HashSet; 4 import java.util.Set; 5 ?6 /** 7 ?* Teacher 8 ?* ?9 ?* @author xiaostudy10 ?*11 ?*/12 public class Teacher {13 ????// id14 ????private Integer id;15 ????// 普通属性16 ????private String name;17 ????// 另一个类的集合18 ????private Set<Student> students = new HashSet<Student>();19 20 ????// 自动生成get、set方法21 ????public Integer getId() {22 ????????return id;23 ????}24 25 ????public void setId(Integer id) {26 ????????this.id = id;27 ????}28 29 ????public String getName() {30 ????????return name;31 ????}32 33 ????public void setName(String name) {34 ????????this.name = name;35 ????}36 37 ????public Set<Student> getStudents() {38 ????????return students;39 ????}40 41 ????public void setStudents(Set<Student> students) {42 ????????this.students = students;43 ????}44 45 }

 1 package com.xiaostudy.domain; 2 ?3 import java.util.HashSet; 4 import java.util.Set; 5 ?6 /** 7 ?* Student 8 ?* ?9 ?* @author xiaostudy10 ?*11 ?*/12 public class Student {13 ????// id14 ????private Integer id;15 ????// 普通属性16 ????private String name;17 ????// 另一个类的集合18 ????private Set<Teacher> teachers = new HashSet<Teacher>();19 20 ????// 自动生成get、set方法21 ????public Integer getId() {22 ????????return id;23 ????}24 25 ????public void setId(int id) {26 ????????this.id = id;27 ????}28 29 ????public String getName() {30 ????????return name;31 ????}32 33 ????public void setName(String name) {34 ????????this.name = name;35 ????}36 37 ????public Set<Teacher> getTeachers() {38 ????????return teachers;39 ????}40 41 ????public void setTeachers(Set<Teacher> teachers) {42 ????????this.teachers = teachers;43 ????}44 45 ????public void setId(Integer id) {46 ????????this.id = id;47 ????}48 49 }

 1 <?xml version="1.0" encoding="UTF-8"?> 2 <!DOCTYPE hibernate-mapping PUBLIC ?3 ????"-//Hibernate/Hibernate Mapping DTD 3.0//EN" 4 ????"http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd"> 5 <!-- 导入包 --> 6 <hibernate-mapping package="com.xiaostudy.domain"> 7 ????<!-- name为bean的类名，table为数据库的表名 --> 8 ????<class name="Teacher" table="t_teacher"> 9 ????????<!-- name为bean的id，column为数据库表的列名 -->10 ????????<id name="id" column="id">11 ????????????<!-- 设置自动更新表，表没有的话创建一个，有的话，再判断结构是否为所需，如有没有想应得列，会自动添加列，多余的也不会删除 -->12 ????????????<generator class="native"></generator>13 ????????</id>14 ????????<!-- name为普通属性，column为数据库表的列名，type为数据类型 -->15 ????????<property name="name" column="name" type="string"></property>16 ????????<!-- name为bean中另一个类的集合名称，table为多对多中间的表，cascade为级联设置自动更新表 -->17 ????????<set name="students" table="t_teacher_student" cascade="save-update">18 ????????????<!-- 自身连接外面的外键 -->19 ????????????<key column="tid"></key>20 ????????????<!-- column为另一个连接的外键，class为另一个bean的类名 -->21 ????????????<many-to-many column="sid" class="Student"></many-to-many>22 ????????</set>23 ????</class>24 </hibernate-mapping>

 1 <?xml version="1.0" encoding="UTF-8"?> 2 <!DOCTYPE hibernate-mapping PUBLIC ?3 ????"-//Hibernate/Hibernate Mapping DTD 3.0//EN" 4 ????"http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd"> 5 <hibernate-mapping package="com.xiaostudy.domain"> 6 ????<class name="Student" table="t_student"> 7 ????????<id name="id" column="id"> 8 ????????????<generator class="native"></generator> 9 ????????</id>10 ????????<property name="name" column="name" type="string"></property>11 ????????<set name="teachers" table="t_teacher_student">12 ????????????<key column="sid"></key>13 ????????????<many-to-many column="tid" class="Teacher"></many-to-many>14 ????????</set>15 ????</class>16 </hibernate-mapping>

 1 <?xml version="1.0" encoding="UTF-8" ?> 2 <!DOCTYPE hibernate-configuration PUBLIC 3 ????"-//Hibernate/Hibernate Configuration DTD 3.0//EN" 4 ????"http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd"> 5 ?6 <hibernate-configuration> 7 ????<session-factory> 8 ????????<!-- 注册驱动 --> 9 ????????<property name="connection.driver_class">com.mysql.jdbc.Driver</property>10 ????????<!-- mysql的用户名 -->11 ????????<property name="connection.username">root</property>12 ????????<!-- mysql的用户密码 -->13 ????????<property name="connection.password">123456</property>14 ????????<!-- 连接mysql的某库 -->15 ????????<property name="connection.url">jdbc:mysql://localhost:3306/user</property>16 ????????<!-- 控制台输出sql -->17 ????????<property name="show_sql">true</property>18 ????????<!-- 格式化输出的sql -->19 ????????<property name="format_sql">true</property>20 ????????<!-- 自动提交事务 -->21 ????????<!-- <property name="connection.autocommit">true</property> -->22 ????????<!-- 创建sql表23 ????????????update：如果没有表，则创建一个。如果有表，而且表结构一致，那么不改变表。如果表结构不一样，会添加sql表缺少的列，多余的也不会删除。24 ????????????create：不管sql表有没有存在，都会重新创建表。25 ????????????create-drop：在create的基础上，每次关闭虚拟机时都会把表删除了。26 ????????????validate：效验sql表，如果一致，则没有反应，如果不一致了，会抛出异常。27 ?????????-->28 ????????<property name="hbm2ddl.auto">update</property>29 ????????<!-- 将Session与线程绑定=> 只有配置了该配置,才能使用getCurrentSession -->30 ????????<property name="current_session_context_class">thread</property>31 ????????<!-- 数据库方言配置 -->32 ????????<property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>33 ????????<!-- 导入映射文件 -->34 ????????<mapping resource="com/xiaostudy/domain/Teacher.hbm.xml"/>35 ????????<mapping resource="com/xiaostudy/domain/Student.hbm.xml"/>36 ????</session-factory>37 </hibernate-configuration>

 1 package com.xiaostudy.test; 2 ?3 import org.hibernate.classic.Session; 4 ?5 import com.xiaostudy.domain.Student; 6 import com.xiaostudy.domain.Teacher; 7 import com.xiaostudy.util.HibernateUtils; 8 ?9 /**10 ?* 测试多对多11 ?* 12 ?* @author xiaostudy13 ?*14 ?*/15 public class Test1 {16 17 ????public static void main(String[] args) {18 ????????//根据hibernate工具类，获取一个全新的Session19 ????????Session session = HibernateUtils.openSession();20 ????????//开始事务21 ????????session.beginTransaction();22 ????????Teacher teacher1 = new Teacher();23 ????????Teacher teacher2 = new Teacher();24 ????????teacher1.setName("t1");25 ????????teacher2.setName("t2");26 27 ????????Student student1 = new Student();28 ????????Student student2 = new Student();29 ????????student1.setName("s1");30 ????????student2.setName("s2");31 32 ????????//维护关系33 ????????teacher1.getStudents().add(student1);34 ????????teacher1.getStudents().add(student2);35 ????????teacher2.getStudents().add(student1);36 ????????teacher2.getStudents().add(student2);37 38 ????????//持久化数据39 ????????session.save(teacher1);40 ????????session.save(teacher2);41 42 ????????//关闭事务并提交事务43 ????????session.getTransaction().commit();44 ????????//关闭资源45 ????????session.close();46 ????}47 48 }